Zoo InternQuest is a seven-week career exploration program for San Diego County high school juniors and seniors. Students have the unique opportunity to meet professionals working for the San Diego Zoo, Safari Park, and Institute for Conservation Research, learn about their jobs, and then blog about their experience online. Follow their adventure here on the Zoo’s website!

On Wednesday, October 28, 2015, the interns met with Dr. Christopher Tubbs, a Scientist at the San Diego Zoo Institute for Conservation Research who works in the Reproductive Physiology Laboratory. In the Reproductive Physiology Laboratory, the main goal for the scientists is to help ensure the reproductive success of the animals at the Zoo and Safari Park. Dr. Tubbs works to preserve and allow endangered and threatened species to have the best possible chance to reproduce.

Dr. Tubbs has been involved with projects involving fertility of southern white rhinos and the marine environment effects on California condors in their reproductive stage. In the lab, Dr. Tubbs does blood tests to determine the hormone levels of the animals. Through the blood test, the scientists can look at the hormones such as their estrogen and progesterone. Progesterone is high during the reproductive cycle. However, it is unrealistic for Dr. Tubbs to take multiple blood samples from the species to determine their hormone levels. Instead, keepers gather urine and feces samples, and then Dr. Tubbs and his team can monitor the animals’ reproductive cycles and their hormone levels.

While working in the Reproductive Physiology Laboratory, Dr. Tubbs gets samples of rhino feces every week. After the feces have been tested, Dr. Tubbs makes a graph of the data from black, southern white and greater one-horned rhinos. When the rhinos show elevated progesterone levels, it means that they are possibly ovulating or pregnant.

The graphs from the hormone data gathered from animal’s feces are very important in certain animals such as pandas. Being solitary by nature, female and male pandas have to stay in separate enclosures because they will become aggressive. When a female panda’s progesterone levels peak, she may be ready for reproduction. Female giant pandas only ovulate a few days out of the year, so it is crucial that the Reproductive Physiology Laboratory notify the keeper once this occurs to introduce the male panda to the female panda otherwise they will miss the opportunity for breeding.

Dr. Tubbs is also working on a diet change for the southern white rhinos to ensure that they are able to reproduce. The pellets, which make up a high percentage of the southern white rhino’s diet contained phytoestrogens that can cause reproductive problems for this species of rhino. In response to this discovery, Dr. Tubbs had bars put in place over the field feeding troughs to keep the southern white rhinos from eating the pellets that contained high levels of phytoestrogens. Dr. Tubbs’ says his job is rewarding because he is able to make a difference in preserving various animal species and is able to raise awareness and to explain how chemicals affect the environments where the different species live.